a single frictionless roller coaster car of mass m=750 kg tops the first hill with speed v=15 m/s ar height h =40m as shown

1) Find the speed of the car at B and C

2) if mass m were doubled, would the speed at B increase, decrease, or remain the same?

a single frictionless roller coaster car of mass m750 kg tops the first hill with speed v15 ms ar height h 40m as shown 1 Find the speed of the car at B and C 2 class=

Respuesta :

Lanuel

1. The speed of the roller coaster car at point B and C: are 19.8 m/s and 0 m/s respectively.

2. If mass (m) of the roller coaster car were doubled, the speed at B would increase because energy is dependent on  the mass of an object.

Given the following data:

  • Mass of roller coaster car = 750 kg
  • Speed of roller coaster car = 15 m/s
  • Height = 40 meters

1. To find the speed of the roller coaster car at point B and C:

First of all, we would determine the potential energy of the roller coaster car by using the formula:

[tex]P.E = mgh[/tex]

Where:

  • m is the mass of object.
  • g is the acceleration due to gravity ([tex]9.8\;m/s^2[/tex]).
  • h is the height of an object.

From the diagram, height at point B = [tex]\frac{h}{2} = \frac{40}{2} = 20[/tex] meters

[tex]P.E = 750(9.8)(20)[/tex]

P.E = 147000 Joules.

Next, we would determine the speed by applying the law of conservation of energy.

[tex]Kinetic\;energy = Potential\;energy\\\\\frac{1}{2} mv^2 = mgh[/tex]

Substituting the values, we have;

[tex]147000 = \frac{1}{2} (750)v^2\\\\147000 = 375v^2\\\\v^2 = \frac{147000}{375} \\\\v^2 = 392\\\\v = \sqrt{392}[/tex]

Speed, v = 19.8 m/s

From the diagram, at point C, the speed is equal to zero (0) meters per seconds.

2. If mass (m) of the roller coaster car were doubled, the speed at B would increase because energy is dependent on  the mass of an object.

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